小编buy*_*pps的帖子

我需要检测图像上的半圆，我找到了以下内容：

import cv2
import numpy as np


def get_circle(img_path):
    im = cv2.imread(img_path, cv2.IMREAD_GRAYSCALE)
    detector = cv2.SimpleBlobDetector()
    keypoints = detector.detect(im)
    im_with_keypoints = cv2.drawKeypoints(im, keypoints, np.array([]), (0,0,255), cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)
    cv2.imshow("Keypoints", im_with_keypoints)
    cv2.waitKey(0)

但是当我尝试运行它时出现以下错误：

Traceback (most recent call last):
  File "D:\giveaway_bot\main.py", line 16, in <module>
    get_circle("blob.png")
  File "D:\giveaway_bot\main.py", line 11, in get_circle
    keypoints = detector.detect(im)
cv2.error: Unknown C++ exception from OpenCV code

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